Alternate Critical Mass
by twinkiesnacker
Summary: What if there were some Tok'ra there during the time when the Trust had infiltrated Atlantis and planted a bomb inside? They would sense any Goa'uld spy! AU of SGA Episode: 2x13: "Critical Mass"


Title: Alternate Critical Mass  
Summary: What if there were some Tok'ra there during the time when the Trust had infiltrated Atlantis and planted a bomb inside? They would sense any Goa'uld spy! AU of SGA Episode: 2x13: "Critical Mass"  
Category: Drama, AU  
Characters: Weir, Sheppard, McKay, Ronon, Teyla|Riknet (My fic "New Friends"), Sarran/Nenesh, Lena/Razan  
Prompt: 121. SGA, any Tok'ra (OC or from episodes), how would an episode with no Tok'ra in be changed if you add Tok'ra?  
Rating: PG-13  
Notes: Written for Tok'ra Kree! 2017

This takes place just after my fic "New Friends". Teyla is getting used to her new symbiote. Sarran|Nenesh has not yet returned to the Milky Way, and Lena|Razan are going to stay in Atlantis, at least for now.

Sarran/Nenesh and Lena/Razan are from the fanfilm Stargate: Lost Colony, so this is a crossover with that.

Also, lots of dialogue borrowed from "Critical Mass". Sorry about that!

* * *

The Tok'ra Sarran|Nenesh walks into the control room and approaches Doctor Elizabeth Weir. He bows his head respectfully. " **Doctor Weir, I will be taking my leave of you and returning to the Milky Way when you next have a scheduled dial-in. I thank you for the hospitality."**

She smiles at him, the worried expression almost disappearing for a moment, then returning. "I understand. Lena will be staying?"

" **Yes, to assist Teyla and Riknet during the early days of their blending. After that she may return, though I suspect she wishes to stay."** He sends Ronon an amused look.

"She doesn't feel comfortable moving to another Galaxy," Ronon quickly adds.

" **That too."**

"I should probably warn you to that two Wraith cruisers are on the way," Weir says.

" **When will they be here?"** Nenesh asks.

"In about a day," McKay says.

" **That is most unfortunate, especially given that you do not currently have the energy to fully protect the city."** Nenesh sighs. " **There are rumors of technology like your 'ZPM' from many worlds. Those of our kind that remains in this Galaxy are following several leads. Hopefully they will soon be successful."  
**

"That would be great!" Weir says. "Just tell us if you need any help with that."

Nenesh nods. " **I believe discretion is paramount as of right now, but we will let you know if there is anything you can do."** He looks to the clock. "There is still time before you dial Stargate Command. I will find Teyla and Riknet, and Lena and Razan and tell them of the Wraith.

"If we're lucky, the Wraith are occupied fighting each other - it looks that way!" McKay says. "But, they're still going in this direction, even if it's accidental."

"The Trust has planted a bomb here on Atlantis! LANDRY: They want the technology, sure, but they're more concerned about the Wraith finding their way to this galaxy. The last thing they need right now is another enemy to contend with – especially one so formidable.

"Teyla has gone to the mainland to visit an old woman who is sick, and who was like a grandmother to her," Sheppard says.

" **I understand. She mentioned she would perhaps do so. In that case I shall talk to Lena and Razan. I am quite certain they wish to stay and fight the Wraith, should they come here, but she will appreciate the information. I will return shortly before it is time to dial Earth."**

* * *

"Are we set to dial?" Weir asks, nodding at Sarran|Nenesh as the Tok'ra enters the room. Lena|Razan enters too, following him.

"Almost. Just finishing data compression," McKay says, as he sits typing at his laptop.

"Stand by," Weir tells them.

"Standing by."

McKay looks up. "Data compression's complete. We're good to go."

"Alright, then." Weir looks over to the technician. "Dial the Gate."

"Yes, ma'am." He presses the first five symbols of the address for Earth.

Just then, a message comes up on Rodney's computer reading, "INCOMING TRANSMISSION" and the transmission begins to feed across the screen.

The technician pushes the sixth symbol. Rodney stares at his screen as he reads the message, then he turns and holds out his hand to the technician.

"STOP!"

* * *

Sarran|Nenesh and Lena|Razan follow Weir, Sheppard, McKay, and Ronon into Weir's office.

"We need to disconnect the ZPM and switch to back-up naquadah generators to prevent any possible dialling of the Gate to Earth," McKay insists.

"I agree. In fact, as of this moment, all Gate activity should be suspended. How many offworld teams do we have out there?" Weir asks.

"Just Zelenka and his team on M7G-677," McKay says.

"Well, unfortunately he's gonna have to sit tight until we sort this thing out."

"Stuck with all those kids!" Sheppard says.

"You're going to have to stay here for now too," Weir tells the Sarran|Nenesh.

"Of course. That is not a problem," Sarran answers.

"Is the Daedalus still in range to relay a data transmission back to SGC?" Weir asks.

McKay nods. "Yes. They are, uh, holding a position that keeps them in range of both Earth and us."

"OK, good. And send a message saying we received their warning and aborted the dialling," Weir says.

"Ask them if they can give us a little more than just "there's a bomb in Atlantis"," Sheppard says.

"Well, it is placed by the Trust. Maybe they think this is the only way to make sure the Wraith don't get there."

"Well, it's drastic but effective," McKay says.

"What's worse is the Trust operative who planted the bomb probably did so under orders from the Goa'uld," Weir tells them.

"What?!" McKay exclaims.

"When did the Goa'uld get involved in this?" Sheppard asks.

"Several months ago. They successfully infiltrated the upper leadership of The Trust, gaining a stronghold on Earth accessing government agencies from many countries," Weir tells them.

"What's a Goa'uld?" Ronon asks. "Wait - they are the ones you guys fought before ending up in this Galaxy, right?" He looks at Sarran|Nenesh.

Sarran nods. "Indeed." He dips his head, giving Nenesh control.

" **They are the same species as the Tok'ra, but their philosophy is... rather different."**

"That is to put it mildly - if Razan's genetic memory is anything to go by," Lena says drily.

Ronon nods. "Right."

"The Tok'ra are _nothing_ like the Goa'uld. Do never think we are!" Lena repeats, looking at Ronon.

"I believe you." He smiles at her.

Weir looks to Sheppard. "I want you to organise some teams to do a search of the city. Start with obvious sabotage points – power distribution centres ..."

"I'll check primary and secondary systems for any anomalous energy readings that might indicate the presence of an explosive device," McKay says.

"And get Cadman to assist you – she's a bomb expert," Sheppards says.

"She is?!" McKay asks.

"She's one of the best – she'll be a big help." Sheppard grins.

" **How may I assist?"** Nenesh asks. " **The Tok'ra have quite a lot of experience with explosives as well, and if it is Goa'uld technology my assistance will be particularly useful."**

"I wish you help too," Lena says.

"Yes, you can both help Sheppard search the city," Weir orders. "Rodney, ask Colonel Caldwell to return to Atlantis to assist with the investigation."

"Whoa-whoa-whoa-whoa-whoa-whoa-whoa. If the Daedalus returns here, then you're effectively cutting off our communication with Earth."

"Yes, I understand that, but if the person who planted the bomb is on board, we're gonna need to question them here – have them reveal the location of the bomb and how to dismantle it. Alright, let's get moving."

* * *

The search goes forward - and is interrupted by the Stargate trying to dial itself. It is a good thing they pulled the ZPM and so it does not have power to dial Earth!

"Whoever planted the bomb must have devised a programme to upload itself and automatically dial the Gate as backup in case the first dialling was halted," McKay observes.

"A very good thing you pulled the ZPM," Weir says.

"Rodney?" Cadman says, noticing something.

"What?"

"The transmitter."

Rodney looks over to the transmitter screen on the wall. "Oh, no!" He runs to it.

"What is this?" Weir asks.

"We just started broadcasting a distress beacon. The Gate dialled itself in order to draw our attention away from the transmitter!"

"Turn it off!" Sheppard orders over the comm.

McKay runs to another laptop. "I am." He types and turns off the transmission. "It's too late. The damage is already done. The two Wraith cruisers I was monitoring – they've-they've-they've, they've picked up the beacon, they've altered their course, they're headed straight for Atlantis."

Sheppard and Sarran|Nenesh walks into the room.

"How long before they get here?" Weir asks.

"A day, maybe a day and a half, depending on if they need to make a hyperspace pause along the way. We'll need to cloak the city again," McKay says.

"Uh, even cloaked, the Wraith are gonna wonder where the beacon came from," Weir points out.

"Well, then, we need a ruse. Umm .. We'll take a transmitter and dump it along with some charred rubble on a beach on the mainland, and they'll think it's jetsam that washed up when the city exploded during the siege." McKay looks pleased.

"Hang on, back up a second. Let me get this straight. You think our bomb guy did this?" Sheppard says.

"Yes. It'd be easy for him to figure out that the Wraith were in the area. We've been tracking them for a while now," McKay says.

"So he gets the Gate to dial by itself in order to distract us so he can broadcast a distress beacon that'll be picked up by ..." Sheppard says.

"... by the Wraith, yes, I believe so," McKay continues.

"OK, why?" Sheppard asks.

"Well, maybe he wants to blow up the Wraith along with the city," Cadman suggests.

"Two cruisers. They're insignificant compared to all the hiveships that are still out there," McKay says.

" **I agree. it does not make much sense,"** Nenesh says.

"Well, we don't have much time, so whatever the connection is, let's try to figure it out before the cruisers get here," Weir orders.

* * *

Sheppard and Sarran|Nenesh walks into Weir's office, seeing her look at a laptop. Sheppard walks around to look at the screen.

"Passenger manifest?" Sheppard asks.

"Yeah," Weir says.

"Any names jump out?" Sheppard wonders.

Weir sighs. "A few, actually. I hate this – having to suspect one of our own."

"Unfortunately the list of suspects may not be limited to the Daedalus," Sheppard points out.

Weir stares at him. "You think the Trust operative might still be here in Atlantis?"

"Well, with everything that's happened: the Gate dialling by itself, the distress beacon ..."

"I don't know – getting themselves blown up along with the city doesn't seem part of their MO."

" **I can at least assure you that there are no Goa'uld here on the station. If there were, I or one of the other Tok'ra would have sensed it,"** Nenesh says.

Weir nods. "That is good to know, at least."

McKay enters.

"Well, even if it is a human..."

Nenesh gives control to Sarran. "Humans can be Wraith worshippers, as strange as that sounds. It is no surprise they will follow a Goa'uld - of course, they may not even know their leader is a Goa'uld."

"True," Sheppard agrees.

"Wow. OK. Who around here do you guys suspect?" Weir asks them all.

They continue to talk about suspects for some time, even thinking some might have been brainwashed. Eventually they are interrupted by the information that Daedalus has landed. Weir goes to meet hum while the others return to searching for the bomb.

* * *

Weir and Caldwell are walking through the corridors, while discussing the imminent threat as well as who the culprit might be.

"I wanna begin the interrogations immediately. All crew and civilian passengers have been confined to their quarters until I have a chance to talk to each of them separately," Caldwell says.

"Colonel. This investigation falls under Atlantis jurisdiction, which means they will be conducted under my command. Now, I welcome your assistance, but as far as questioning potential suspects ..." Weir insists.

Caldwell interrupts her, "Doctor. One of the people aboard my ship may be an operative of The Trust."

"Yes. And the sooner I figure out who that is, the better for all of us."

Caldwell looks irritated. "Alright, who's first on your list?"

"Kavanagh," Weir says.

* * *

After an unpleasant interview with Kavanagh, who is quite an unpleasant man, Weir continues with her interviews, trying to determine who the undercover Trust operative is.

Eventually, she is interrupted by McKay on the comm, who calls to give Weir important information.

"Can you come to the Control Room? I've discovered something important," McKay tells her.

"I'm on my way."

* * *

"What have you found?" Weir asks, looking at the other people in the room - Sheppard, McKay, and Sarran|Nenesh.

"Guess what? Turns out there's no bomb after all," Sheppard says.

"Uhhhh, there's no actual explosive device. The explosion will come, but, uh, from somewhere else. Now, with the Wraith on the way, we'll need to cloak the city, right?" McKay says.

"Yes," Weir agrees.

"Well, in order to do that, we need to reconnect the ZPM in order to supply the necessary power," McKay continues.

"And what about the Stargate?" Weir asks.

"Ah – I've physically disabled the DHD. It won't be able to dial, so it won't be a problem. Now, the ZPM, however, *will* be. Now, as you know, the Zero Point Module controls the flow of massive amounts of power."

"Like a dam," Sheppard suggests.

"No, it's not like a dam, it's more like a ... uh ... actually, yes, it's like a dam. If you overload the dam, it breaks, which is why the Ancients put in place failsafes to prevent such a thing from happening," McKay says.

"Like a spillway."

McKay gets irritated. "Could we just stick with failsafes?"

Sheppard shrugs and Sarran grins.

"The problem is, our Trust operative figured out a way to rewrite Atlantis' operating system and disable the failsafes, but mask it in such a way that the city sensors didn't detect it," McKay continues.

"So the dialling of Earth would cause the ZPM to overload," Weir concludes.

"Oh, yeah! And given that dialling another galaxy requires tremendous amounts of power, we're talking catastrophic overload. I mean, the explosion would destroy not just the city, but, uh, most likely the entire planet."

"Can the failsafes be re-enabled?" Saran asks.

"Yes, but, uh, whoever it was who did this anticipated the possibility that it would be discovered and they put in place a code to block access to it," McKay says.

"And I'm gonna guess that cracking this code isn't gonna be easy," Sheppard says.

"No, not at all. It is extremely complicated," McKay says.

"But for now you've already disabled the DHD so it's impossible to dial Earth," Weir points out.

"Yeah, but unfortunately, any number of systems can be used in conjunction with each other to, uh, overload the ZPM. It'd be a much more gradual build-up than dialling the Gate, which would cause an instantaneous power spike, but, um, equally as effective in its results," McKay tells them.

Weir nods. "And we can't disconnect the ZeePM because we need the cloak for when the Wraith cruisers arrive."

"Bingo! Which is why our bomber activated the distress beacon, alerting them. And *that* is how the Wraith coming to Atlantis is connected to detonating the bomb."

"Perhaps Nenesh should take a look at the code. If it was written by a Goa'uld, and just installed by a human, he may have a better chance at breaking it," Sarran says.

"I think I have it under control," McKay insists.

"Work together. I need to get back to the interviews. If we could find the spy, this would be much easier."

* * *

Weir returns to interrogating Kavanagh, since he seems the most likely person to work for the Trust. He admits nothing, and Weir starts to consider if torture will work.

Sending Kavangah away for now, she goes to the control room to check on the status of the Wraith cruisers. They are still approaching.

"Could the cloaking cause the ZPM to overload?" she asks.

"Yes, but I can, uh, turn off some of the systems to keep the power levels short of an overload," McKay says.

"Maybe we should start thinking about evacuating the city," Sheppard suggests.

"Well, there's not a lot of options there. Still, it can't hurt to have a plan ready, if we can think of one," McKay says.

"Any luck on cracking the access code?" Weir asks.

"Not yet. Nenesh is sure it's a Goa'uld code," McKay tells them.

"All right. Tell him to continue working on it. I need you to join us in the conference room, then you can go help Nenesh with the code afterwards," Weir decides.

* * *

"How are things coming with Kavanagh? He still your prime suspect?" Caldwells asks.

"Yes, he is. I'm having some difficulty with him, though. He's not exactly the most co-operative of people," Weir says.

"Ooh, well, *there's* a shocker!" McKay says.

"If he does know the code, I highly doubt he's gonna just give it to us," Weir says.

Ronon enters from the balcony, having heard them. He draws his knife. "Give me ten minutes with him. I'll get it out of him."

"Might not be a bad idea. Maybe it *is* time to take this interrogation to the next level," Sheppard suggests.

"Look, I hate Kavanagh as much as the next guy – probably even more – but, um, we really need to be sure about this," McKay says.

"I agree. If there's the slightest chance that he's innocent, then ..." Weir says.

"We don't have time to debate morality. Unfortunately sometimes you have to do unpleasant things to save lives," Caldwell says.

"Hm. How is Nenesh doing with the decryption of the access code?" Weir asks.

"He believes he can crack, but you know these people - they've got pretty high opinion of themselves," McKay says.

Sheppard snorts.

"What?" McKay looks offended at the implication that _he_ is arrogant. "I have reason!"

Caldwell frowns. "Who is Nenesh?"

" **I am Nenesh - and you are a Goa'uld!"** Nenesh exclaims, as he walks into the room.

" **Tok'ra!"** Caldwell hisses and flashes his eyes. " **Why was I not informed some of that traitorous scum was here?"** He pulls out his sidearm and jumps to grab Weir as a hostage.

Before he has a chance to do so, Nenesh grabs the zat he has in his belt and fires, stunning Caldwell.

"Caldwell is a Goa'uld?" McKay says, shocked.

"Secure him!" Weir orders.

Sheppard and Ronon quickly disarms Caldwell who is already waking up, and pulls him to his feet.

" **You will all die when the Wraith come here - your only choice is powering up the ZPM and that will set off the bomb. You are doomed!"** Caldwell spits at them.

"Then so are you unless you tell us how to disarm the code!" Sheppard exclaims.

" **The Trust cannot let the Wraith take this city - and it is only a matter of time before they do. Then they will come to the Milky Way. No, we had to act before you recklessly endangered us all!"** Caldwell says.

"That's not really the usual MO of you guys, though, is it? Being blown up, selfishly, to save the rest of the Galaxy?" Sheppard says mockingly. "Perhaps you would care to give us the access code?"

" **I will _never_ give you the code, and you pathetic losers will never crack it!" **Caldwell exclaims.

" **That was what I was coming here to say, before _you_ showed your face!" **Nenesh gives Caldwell a derogatory look. " _ **I**_ **have cracked the code. It was quite simple."**

" **Accursed Tok'ra!** " Caldwell screams and struggles against the holds of Ronon and Sheppard. " **Do you not understand you doom everyone in the Milky Way?"**

"Listen," McKay says, calling their attention to himself. "If you don't mind - important info here. The Wraith cruisers are getting closer. I think it's time to reconnect the ZPM and cloak the city. _Especially_ as there's apparently no longer a danger from an overload?" He looks at Nenesh, somewhat disbelieving.

" **There is no longer any danger, no."**

Weir nods, pleased. "Go ahead and cloak it then."

* * *

In the ZPM room, the ZPM is back in its slot. The city is cloaked.

"How're we doing?" Weir asks.

"The cloak is functioning as it should, as is all other systems. With no risk of an overload, we should be fine. As long as the Wraith take the bait and believe the signal came from a crash, of course," McKay says.

"Let's hope they do," Weir agrees.

"They're here!" McKay informs them, looking at the displays. "Two Wraith cruisers, just outside our atmosphere."

"So far they don't behave in a way that would indicate they're aware of us."

* * *

After some time, the Wraith cruisers continue on, not having noticed anything. The people in Atlantis can relax.

"What about the Goa'uld?" Weir says. "I seem to remember something about you guys being able to remove them."

Sarran nods. "We can. The Tok'ra who has remained in the Milky Way has more experience with this, naturally, but they would be happy to help. However, that may not be necessary in this case. Your Asgard associate, Hermiod, believes he can remove the symbiote with an Asgard transportation beam. If that works, it would probably be safer. Goa'uld have a tendency to fight when they are being removed and may injury or kill their host."

Weir nods. "Then let's hope Hermiod can handle it."

"He has begun initial calculations on the extraction," McKay says.

"I will be most interested in learning more of the procedure, as will the rest of the Tok'ra," Sarran.

"I think we can promise you access to the data." Weir smiles. "After all, we've got you to thank for saving the station."

Sarran nods. "It is a good thing Teyla and her symbiote, Riknet, will be staying here, and possibly also Lena and Razan. The presence of Tok'ra means it will be discovered pretty quickly if anyone here is implanted with a Goa'uld."

"I agree. In fact, I think we should increase the Tok'ra presence here if possible. Especially those who have lived here in the Pegasus Galaxy has a lot of experience you can share with us."

They all turn to see Radek Zelenka returning from the mission to the planet with the many kids. He is stomping down the corridor, glowering at them all. His face is painted several different colours and white straw has been woven into his hair.

"It's Mister Mom! How were the kids?" McKay asks, grinning.

Zelena looks at him furiosly, finally get out the words in spite of his rage, "Do not even speak to me." He leaves.

The others smile at each other, then return their thoughts to the threats of the Wraith and of the Goa'uld.

"We should be happy the Wraith have started fighting each other. That is something, at least," Sheppard says.

"Yes, and that no one on the base is a Goa'uld. That is also good," McKay says.

Weir sighs, just happy they did not end up torturing Kavanagh.


End file.
